Developers for photographic silver halide papers



United States Patent-O DEVELOPERS FOR PHOTOGRAPHIC SILVER HALIDE PAPERS Ernst Tausch, Berlin-Charlottenburg, Germany, assignor to Photographica G. in. b. H., Berlin-Charlottenburg, Germany, a corporation of Germany No Drawing. Application April 8, 1953, Serial No. 347,603

Claims priority, application Germany April 10, 1952 5 Claims. (Cl. 96-66) This invention relates to new developers for the treatment of photographic silver halide papers.

It is known that under unfavorable conditions photographic papers incline to produce a yellowish fog, mainly consisting of colloidal silver. Alsothe oxydation products of the developing agents may cause a similar yellowish discoloration of the layer and the support of photographic papers if the developer is exhausted and colored brown. A yellowish or off-white tint of the photographic prints also may be caused by a not pure White color of the paper support itself.

The mentioned discolorations are caused by an absorption of light in the short-wave part of the visible spectrum between about 4000 A. and about 5500 A. According to the present invention these discolorations are inhibited by special additions to the developers which v to the paper It is already known, that textiles and papers are treated to brighten their whites with fluorescent organic compounds, so called optical bleaching agents. For photographic papers such compounds are proposed for the same purpose as additions to the layers. that it is much better for various reasons, to use these compounds in developers for photographic papers. Thus said compounds cannot affect the properties of the photographic layers, which are very sensitive in this regard especially during storage. which cannot be added in technical pure form to the photographic layers may be used so in the developers. Also there are more possibilities When using the fluorescent compounds in the developers to get best suited effects for the prints by additions chosen optimally by kind and quantity, as if the layers of the photographic papers would already contain such a compound.

It was surprising and not to be foreseen, that said fluorescent organic compounds without injury of their efliciency could be added to the developers, since it is the usual practice to remove optical bleaching agents from textiles by treatment with soda solution. It was found, that the said fluorescent organic compounds can be used without trouble if they were chosen in the right manner and quantity.

Fluorescent organic compounds which can be used according to the present invention as additions to the developers for photographic papers, have been described in the literature. Especially suited for this purpose are,

Many of said compounds It was found,

for example, the derivatives of the 4,4'-diaminostilbene- 2,2 '-disulfonic acid according to the following formula:

| S OaMe $03M? in which Me represents a-substituent selected from the group consisting of alkali metal, alkali earth metal, ammonium and substituted ammonium, while A and A may be the same and each represents a substituent selected from the group consisting of CO-R CONH-R and wherein R represents a substituent selected from the group'consisting of aryl and substituted aryl, R represents a substituent selected from the group consisting of hydrogen, alkyl, aryl and substituted aryl, R represents an amine residue, and R represents a substituent selected from the group consisting of Cl, OH, NH and an amine residue.

Symmetrical compounds according to this formula are:

I. 1 4,4-di-[acylamino1-stilbenes RvCO-NH OH=CH NH-CO-Rr EEOaMe SOaMe 4,4-di-[ureido]-stilbenes m-NH-o O-NH- III.

l S OaMe SOiMe Also according to this formula are unsymmetrical stilbene derivatives, described in the literature, which may be obtained from the 4-nitro-4'-aminostilbene-2,2'-disul- .1 fonic acid, e. g. 4-[ureido]-4-[acylamino]-stilbenes or 4-[triazin-(l",3",5")-yl-(2") amino] -4' [acylaminolstilbenes. v

Suitable compounds are, for example:

(1) Sodium 4,4-di-(benzamido)-stilbene-2,2-disu1fonate (2) Sodium 4,4'-di-(p-aminobenzamido)-stilbene-2,2'-disulfonate (3) Sodium 4,4-di-(p-acetaminobenzamido)-stilbene-2, 2 -disulfonate v (4) Sodium 4,4'-di-(2,5-dimethoxybenzamido)-stilbene- 2,2'-disulfonate (5) Sodium 4,4'-di-(p-methylaminobenzamido)-stilbene- '2,2-disulfonate (6) Sodium 4,4'-di-(methylureido)-stilbene-2,2-disulfonate (7) Sodium 4,4'-di-(pheny1ureido)-stilbene-2,2'-disulfonate (8) Sodium 4,4'-di-(p-tolylureido)-stilbene-2,2'-disulfo nate (9) Sodium 4,4-di-(p-chlorphenylureido)-stilbene-2,2'-

disulfonate (15) 'Sodium azin (l",3",'5") yl (2") amino] l stilbene 2,2- disulfonate (17) Sodium 4-phenylacetamino 4' [4",6-diamino;tri-

azin (1,3",5") yl (2") amino] stilbene 2,2-

disulfonate (18) Sodium 4 acetamino 4 (phenylureido) stilbene-2,2-disulfonate (19) Sodium 4 (2"-ethoxy 4" methyl-benzarnido)- 4'-(phenylureido) -stilbene 2,2'-disulfonate It should be emphasized, that the said compounds themselves-are not the subject ot: thepresent= inventiom .since they r do not: limitthe fluorescent organic :compoundst snited as additions aecording todhis invention to developers :for photographic papers, they are mentioned as examples only;

' The above mentione'd compounds have the mutual property to attach themselves in a substantive mannerto the support and the-layers of-*thephotographic-"papers.

As developers for .photographicpapers which accord! ing to the present-invention can be'improved by addition of fluorescent organic compounds, allkinds' of-developers may be cited which normally are used between exposure and drying for the treatment of photographic silver halide papers. Developersaccording to this in vention have special advantages for papers designed for usein connection with color photography, in particular multi-layer color papers. The present invention will be illustrated by the following examples without limiting it by the discussedwases:

is 'added' 0.2 g. of sodium 4,4'-di-(phenylureido)-stilbene- 2,2'-disulfonate. It produces photographic prints. with much purer and brighter whites than .the same developer withoutthis addition. 'Theoth'er properties ofi'the developer'will not be changedby'the addition.

EicamplezZ To a manufactured paper developer of. the composition:

Grams .I. p-methylaminophenolsulfate-. 1'5 Hydroquinone '60 II.-Sodium* sulfite (desicc.) 225 Sodium carbonate (desicc.) 340 Potassium bromide 1 10 is added (in II) 2.5 g. sodium 4,4-di-[4"-hydroxy-6'"- disulfonate. -I' and' II were dissolved' succes'sively in-S li'tl'pfwater: In use, 1 part developer is diluted with 2 partsofwater.

This developer produces with all kinds of photographic papers purer and brighter whites than the same developer without the addition according to this invention.

Sodium sulfite (desicc.) 1 Potassium carbonate Potassium. br 0.5

Water to 1000 um.

is added. 0.2 g..-of-the-.same. stilbene 'derivate as-inExample 2. It produces a better white at the development of the color-prints on multilayer'color' papers than without the addition.

'Variouschanges and modificationsjmay be made without departing from the'spirit and scope of the present invention =and-it is intended that such obvious changes and *modificationstbe"embraced by the annexed claims.

Having thus described the invention,.what is claimed as-new an'd-desiredto be secured :by Letters Patent, is: l.-'-In-'the 'process of producing photographic images withimproved i whiteness, the :step of processing exposed light-sensitive silver"halide-coated papers with a silver halide developer-having 'dissolved therein a substantially colorless derivative of 4,4'-diamino-stilbene-2,2-disulphonic acid, said derivative'absorbing ultraviolet radiation of between about"3', 000 'Angstrom units and 4,000 Angstrom units and emittingifiuorescent light of between about"4,000-'Angstrom"units and 5,500 Angstrom units and having'the formula:

some SOaMe inwhich Me' represents .a substituent .selected from the 'group 'consisting'of "alkali metal, alkali earth metal and ammonium; while 'A and Ag each represents a substituent selected 'from: the group consisting of CO'-R CO NH R and wherein'R' represents aryl, R represents a substituent selectedtfromthe: group consisting of hydrogen;.alkyl and aryl, R representsamino andlRu represents a substituent selected from the group;consis;ting of,,.Cl, OH and amino.

2. Therprocess.accordingto claim-l; wherein the derivativeof 4,4-diamino stilbene2,2rdisulphonic acid is the sodium salt of 4,4'.-di-(phenylureido)-stilbene-2,2-disulphonic acid.

3. 'The process according to. claim 2, said sodium ,salt of 4,4-di'-'(phenylureido) stilbene-2,2'-disulphonic acid being present in an amount ranging'between about 0.05 and LO'gram' per liter of developer.

4. The process according to claim 1; wherein the derivative of I 4',4 '-diamin0*stilbene-2",2'-disulphonic acid is the sodium salt of 4;4''-'di-[4"'-hydroxy-6'-anilino-triazin- (l"',3",5'-") ---yl (2") --amino] stilbene 2,2' 'di-sulphonic acid.

5.: The 1 process. according. to claim 4, said sodium salt of 4,4 di [4" hydroxy 6-. -.anilino triazin- (-1.,3'.,5) yl..-h(2") amino] stilbene 2,2 disulphonic acid being presentiman amount ranging between about 0.05 and...l.0.:gram,per1liter of-developer. 7

(References on following page) References Cited in the file of this patent UNITED STATES PATENTS 6 FOREIGN PATENTS 878,823 France Nov. 2, 1942 498,125 Belgium Jan. 2, 1951 502,230 Belgium Apr. 14, 1951 (Corresponding to Great Britain No. 672,803, May 28, 1952) 

1. IN THE PROCESS OF PRODUCING PHOTOGRAPHIC IMAGES WITH IMPROVED WHITENESS, THE STEP OF PROCESSING EXPOSED LIGHT-SENSITIVE SILVER HALIDE-COATED PAPERS WITH A SILVER HALIDE DEVELOPER HAVING DISSOLVED THEREIN A SUBSTANTIALLY COLORLESS DERIVATIVE OF 4,4''-DIAMINO-STILBENE-2,2''-DISULPHONIC ACID, SAID DERIVATIVE ABSORBING ULTRAVIOLET RADIATION OF BETWEEN ABOUT 3,000 ANGSTROM UNITS AND 4,000 ANGSTROM UNITS AND EMITTING FLUORESCENT LIGHT OF BETWEEN ABOUT 4,000 ANGSTROM UNITS AND 5,500 ANGSTROM UNITS AND HAVING THE FORMULA: 